Dissertation/Thesis Abstract

Analysis of Contact Mechanics in Nanoscale in Nanoelectromechanical Switches
by Zandigohar, Mehrdad, M.S., Southern Illinois University at Edwardsville, 2020, 85; 28031329
Abstract (Summary)

Micro- and nanoelectromechanical (M/NEM) relays consist of three elements, a source, a drain and a gate that is used to actuate the relay. The drain is often a flexible beam which deforms and acts as a switch by making or breaking physical contact with drain. M/NEM relays maintain zero-leakage current in OFF-STATE with sharp ON-OFF transition and CMOS compatibility that make them a great candidate in small scale applications and low-power operations. Other applications include static random-access memory (SRAM), cell design or non-volatile memories including non-volatile content-addressable memory (CAM) due to their hysteresis behavior and stiction. Besides, field-programmable gate arrays (FPGA) has shown better performance by the use of NEM-only and hybrid CMOS-NEM relays. Despite their promising advantages, NEM switches have their own shortcomings including fatigue, low life cycle and high contact resistance that degrades over switching cycles. Furthermore, stiction is still an issue in nanoelectromechanical relays due to the compliance of the system and relatively high adhesion forces. In our current research, we first study the most common and state of the art mechanical relays, and determine the contact forces and that how they relate to the ON-STATE contact resistance. The study is conducted for different geometries, sizes and contact materials. The reaction forces and electrical characteristics are then analyzed and contact resistance as the primary contact measure of relay performance was investigated. The results of this study exhibited a direct link between contact pressure and contact resistance, where the apparent contact area does not contribute explicitly to contact properties. Next, a novel design approach for laterally actuated NEM relays is proposed that can overcome large adhesion force preventing potential permanent stiction and catastrophic failure. Our design involves a curved structure for the contact between the source and drain adding a nonlinear and extra mechanical stiffness that allows the surfaces to separate under large adhesion force. This design can also improve contact resistance by increasing the effective contact area.

Indexing (document details)
Advisor: Shavezipur, Kamran
Commitee: Kweon, Soondo, Wang, Fengxia
School: Southern Illinois University at Edwardsville
Department: Mechanical Engineering
School Location: United States -- Illinois
Source: MAI 82/3(E), Masters Abstracts International
Subjects: Mechanical engineering
Keywords: Asperity, Contact resistance, N/MEM relays, Reaction force, Stiction
Publication Number: 28031329
ISBN: 9798672113814
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